Neem based composition for coating nitrogenous fertilizer

ABSTRACT

A neem based composition for coating nitrogenous fertilizer. The composition comprises 2-10 percent by weight neem extract, 10-60 percent by weight neem oil, 10-25 percent by weight binder and 25-50 percent by weight organic solvent. Also a method of making the composition by mixing the ingredients, a method of coating a nitrogenous fertilizer by mixing it with 0.5 to 1.0 percent by weight of the neem based composition and nitrogenous fertilizer coated with 0.5 to 1.0 percent by weight of the neem based composition.

FIELD OF INVENTION

This invention relates to a neem based composition for coating nitrogenous fertilizer.

This invention also relates to a method of making the neem based composition, method of coating nitrogenous fertilizer with the composition and nitrogenous fertilizer coated with the composition.

PRIOR ART

Urea is the major nitrogenous fertilizer being used on crops worldover. Immediately on application to soil, urea undergoes chemical/biochemical transformations through hydrolysis and nitrification. Hydrolysis takes place in the presence of water and enzyme called urease and results in the breakdown of amide form of nitrogen into ammoniacal nitrogen or ammonium carbonate. The resultant ammoniacal nitrogen undergoes further transformation ie nitrification in the presence of oxygen and soil bacteria (Nitrosomonas sps. and Nitrobacter sps.) to give nitrite and nitrate forms of nitrogen. Hydrolysis and nitrification of urea fertilizer are to a large extent completed in 15-20 days under most atmospheric conditions, whereas most cultivated crops generally take more than 90-100 days to complete their lifecycle. Nitrates are highly water soluble and when formed in large quantities in excess of the limited quantities required by the crops at early stages of their growth due to rapid hydrolysis and nitrification of urea, they are liable to be leached down the soil profile beyond the active root zone of crops. This reduces use efficiency of urea fertilizer by crops. Moreover, under water logged conditions, nitrates are reduced to nitrous oxide and elemental nitrogen by the action of soil bacteria to meet their oxygen demand. This leads to development of nitrogen deficiency and poor crop yields.

Besides the economic losses on account of poor crop yields, losses of fertilizer nitrogen mainly in the form of leaching of nitrates and emission of nitrous oxide, being a green house gas, pose serious environmental hazards. World Health Organisation of United Nations has in fact prescribed a maximum limit of 50 mg/litre for nitrates in drinking water. This is mainly because higher nitrate content in drinking water eventually may lead to blood cancer (Methaemoglobinae mia) in new born babies. Nitrous oxide on the other hand has a very significant 310 times more global warming potential via-a-vis the other green house gas carbon dioxide. Therefore, any development leading to reduction in leaching and denitrification of fertilizer nitrogen would not only enhance crop use efficiency and productivity but also ensure environmental safety.

Constituents of neem and other non-edible oilseeds such as karanj, mahua or castor are reported to be effective nitrogen inhibitors (Devkumar and Sukhdev, 1993, In. Neem Research and Development, Society of Pesticide Science, New Delhi 63-96; Prasad and others, 1971, Advance in Agronomy, 23, 357-383; Prasad and others, 1996, In, Neem Research and Development, New Age International Publishers, New Delhi, 121-132). Coating of urea with neem cake or neem oil alone or in combination with neem fatty acid distillation residue is reported (Indian Patents Nos 185675 and 193152 and 1 K Suri and other 2000, Fertiliser New 71-72)

OBJECTS OF INVENTION

An object of the invention is to provide a neem based composition for coating nitrogenous fertilizer, which composition reduces denitrification and leaching losses of the nitrogenous fertilizer.

Another object of the invention is to provide a neem based composition for coating nitrogenous fertilizer, which composition increases the efficiency of use of the fertilizer by the crops and the yield of crops.

Another object of the invention is to provide a method of making a neem based composition for coating nitrogenous fertilizer, which composition reduces denitrification and leaching losses of the nitrogenous fertilizer.

Another object of the invention is to provide a method of making neem based composition for coating nitrogenous fertilizer, which composition increases the efficiency use of the fertilizer by the crops and the yield of crops.

Another object of the invention is to provide a method of coating a nitrogenous fertilizer with a neem based composition which reduces denitrification and leaching losses of the nitrogenous fertilizer.

Another object of the invention is to provide a method of coating a nitrogenous fertilizer with a neem based composition which increases the efficiency of use of the fertilizer by the crops and the yield of crops.

Another object of the invention is to provide a nitrogenous fertilizer coated with a neem based composition which reduces denitrification and leaching losses of the nitrogenous fertilizer.

Another object of the invention is to provide a nitrogenous fertilizer coated with a neem based composition which increases the efficiency of use of the fertilizer by the crops and the yield of crops.

Another object of the invention is to provide urea or urea prills coated with a neem based composition which reduces denitrification and leaching losses of urea.

Another object of the invention is to provide urea or urea prills coated with a neem based composition which increases the efficiency of use of the fertilizer by the crops and the yield of crops.

DETAILED DESCRIPTION OF INVENTION

According to the invention there is provided a neem based composition for coating nitrogenous fertiliser, the composition comprising 2-10 percent by weight neem extract, 10-60 percent by weight neem oil, 10-25 percent by weight binder and 25-50 percent by weight organic solvent.

According to the invention there is also provided a method making a neem based composition for coating nitrogenous fertilizer, the method comprising mixing 2-10 percent by weight neem extract, 10-60 percent by weight neem oil, 10-25 percent by weight binder and 25-50 percent by weight organic solvent.

Preferably, the composition comprises 5 percent by weight neem extract, 40 percent by weight neem oil, 15 percent by weight binder and 40 percent by weight organic solvent.

Preferably, the neem extract in the composition contains 5 to 10 percent by weight triterpenes. Preferably the triterpenes in the neem extracts comprise salanin and deacetyl salanin.

The binder is selected from synthetic polymers, gum Arabica or rosin and is preferably rosin. The organic solvent is selected from Xylene, Aromax, C-IX or deodorized kerosene and is preferably deodorized kerosene.

Preferably, the composition has a density of 0.93-0.96 g/cc, organic carbon content of 70% w/w, minimum, total nitrogen content of 0.45-0.55%, w/w, moisture content of 2.0% w/w maximum by Karl Fischer and methanol solubles content of 20.0% w/w, minimum.

According to the invention there is also provided a method of coating a nitrogenous fertilizer, which comprises mixing the nitrogenous fertilizer with 0.5 to 1.0 percent by weight of the neem based composition described above.

According to the invention there is also provided a nitrogenous fertilizer coated with 0.5 to 1.0 percent by weight of the neem based composition described above.

Preferably the nitrogenous fertilizer comprises urea or urea prills coated with 0.5 to 1.0 percent by weight of the neem based composition described above.

Studies were carried out using typical neem based compositions of the invention comprising 5% by weight neem extract, 40% by weight neem oil, 15% by weight rosin pitch and 40% by weight deodorized kerosene and having density of 0.93-0.96 g/cc, organic carbon content of 70% w/w, total nitrogen content of 0.45-0.55% w/w, moisture content of 2.0% w/w by Karl Fischer and methanol solubles content of 20.0% w/w. The compositions were formed by mixing the ingredients together with varying percentages of triterpenes as stated below. Urea was coated with the compositions by mixing it with the compositions. The study details were as follows:

The influence of the coating of urea with the composition of the invention on emission of nitrous oxide (denitrification) in two soils under laboratory conditions up to 35 days was studied and the results were as shown in the following Table 1.

TABLE 1 Total N₂O (mg/kg soil) Treatments Alkaline/soil (pH 7.8) Acidic Soil (pH 5.6) Uncoated Urea 25539.9 28.4 N₁C₁-Coated Urea 23613.2 28.1 N₁C₂-Coated Urea 21517.8 23.2 N₁C₃-Coated Urea 20446.8 22.8 N₂C₁-Coated Urea 18615.4 19.3 N₂C₂-Coated Urea 13940.3 16.8 N₂C₃-Coated Urea 11961.6 16.0 N₃C₁-Coated Urea 18111.2 18.7 N₃C₂-Coated Urea 13913.2 17.3 N₃C₃-Coated Urea 10989.4 16.6 C. D. (p = 0.05) 1473.2 1.8 N₁ = Composition comprising neem extract containing 2% triterpenes N₂ = Composition comprising neem extract containing 5% triterpenes N₃ = Composition comprising neem extract containing 10% triterpenes C₁ = Coating thickness of 0.3% w/w of urea C₂ = Coating thickness of 0.5% w/w of urea C₃ = Coating thickness of 1.0% w/w of urea

The influence of the coating of urea with the composition of the invention on emission of nitrous oxide as well as accumulation of nitrate through leaching in rice soil under field conditions (duration 75 days) were studied and the results were as shown in the following Table 2.

TABLE 2 Leaching Losses Dentrication Loss Treatments NO₃ + NO₂ Kg/ha N₂O N Kg/ha Uncoated Urea 30.4 7.8 N₁C₁-Coated Urea 28.6 6.4 N₁C₂-Coated Urea 27.3 5.3 N₁C₃-Coated Urea 27.0 5.2 N₂C₁-Coated Urea 25.3 5.0 N₂C₂-Coated Urea 20.4 4.6 N₂C₃-Coated Urea 19.3 4.4 N₃C₁-Coated Urea 23.4 5.0 N₃C₂-Coated Urea 19.6 4.5 N₃C₃-Coated Urea 19.2 4.5 C. D. (p = 0.05) 4.3 0.7

The influence of the coating of urea with the composition of the invention on reduction in leaching losses and volatilization losses under field conditions (wheat-sampling duration: 70 days) was studied and the results were as shown in the following Table 3.

TABLE 3 Leaching Losses Volatilisation Treatments NO₃ + NO₂—N Kg/ha NH₄—N Kg/ha Uncoated Urea 15.7 21.3 N₁C₁-Coated Urea 14.3 21.4 N₁C₂-Coated Urea 14.1 20.6 N₁C₃-Coated Urea 13.7 19.8 N₂C₁-Coated Urea 11.6 19.5 N₂C₂-Coated Urea 9.6 18.6 N₂C₃-Coated Urea 9.0 18.2 N₃C₁-Coated Urea 11.4 19.6 N₃C₂-Coated Urea 9.1 19.2 N₃C₃-Coated Urea 9.0 18.8 C. D. (p = 0.05) 1.8 1.9

The influence of the coating of urea with the composition of the invention was studied in field conditions on grain yield of wheat and rice and the results were as shown in the following Table 4.

TABLE 4 Wheat Rice Treatments Tons/ha Tons/ha Uncoated Urea 3.03 4.73 N₁C₁-Coated Urea 3.89 5.04 N₁C₂-Coated Urea 4.11 5.91 N₁C₃-Coated Urea 4.26 6.23 N₂C₁-Coated Urea 4.18 6.47 N₂C₂-Coated Urea 5.63 7.21 N₂C₃-Coated Urea 5.81 7.20 N₃C₁-Coated Urea 4.81 6.95 N₃C₂-Coated Urea 5.61 7.40 N₃C₃-Coated Urea 5.93 7.26 C. D. (p = 0.05) 0.42 0.52

As can be seen in the Tables 1 to 4, the neem oil based composition of the invention reduces denitrification and leaching loses of nitrogenous fertilizer particularly urea and increases efficiency of use of urea by the crops and yield of crops. As emission of nitrous oxide is reduced, green house effect and resultant environmental problem is reduced. According to the invention, the constituents of the composition of the invention are selected and used in the optimum proportions with appropriate percentage of triterpenes so as to obtain a composition having improved activity. The neem extract provides the requisite amount of triterpenes; the neem oil acts as a spreading agent; and desired viscosity is imparted to the composition by the rosin pitch and deodorized kerosene. 

1. A neem based composition for coating nitrogenous fertilizer, the composition comprising: 2-10 percent by weight neem extract, 10-60 percent by weight neem oil, 10-25 percent by weight binders and 25-50 percent by weight organic solvents wherein the neem extract contains 5 to 10 percent by weight triterpenes, and the composition has a density of 0.93-0.96 g/cc, an organic carbon content of at least 70% w/w, a total nitrogen content of 0.45-0.55% w/w, a moisture content of 2.0% w/w or less as measured by Karl Fischer, and a methanol solubles content of at least 20.0% w/w.
 2. A composition as claimed in claim 1, which comprises 5 percent by weight neem extract, 40 percent by weight neem oil, 15 percent by weight binder and 40 percent by weight organic solvent.
 3. A composition as claimed in claim 1, wherein the triterpenes comprise salanin and deacetyl salanin.
 4. A composition as claimed in claim 1, wherein the binder is rosin and the organic solvent is deodorised kerosene.
 5. A method of making a neem based composition for coating nitrogenous fertilizer, the method comprising: mixing 2-10 percent by weight neem extract, 10-60 percent by weight neem oil, 10-25 percent by weight binder and 25-50 percent by weight organic solvent, wherein the neem extract contains 5 to 10 percent by weight triterpenes, and the composition has a density of 0.93-0.96 g/cc, an organic carbon content of at least 70% w/w, a total nitrogen content of 0.45-0.55% w/w, a moisture content of 2.0% w/w or less as measured by Karl Fischer, and a methanol solubles content of at least 20.0% w/w.
 6. A method as claim in claim 5, wherein the composition comprises 5 percent by weight neem extract, 40 percent by weight neem oil, 15 percent by weight binder and 40 percent by weight organic solvent.
 7. A method as claimed in claim 5, wherein the triterpenes comprise salanin and deacetyl salanin.
 8. A method as claimed in claim 5, wherein the composition comprises rosin as binder and deodorised kerosene as organic solvent.
 9. A method of coating a nitrogenous fertilizer which comprises mixing the nitrogenous fertilizer with 0.5 to 1.0 percent by weight of the neem based composition as claimed in claim
 1. 10. Nitrogenous fertilizer coated with 0.5 to 1.0 percent by weight of the neem based composition as claimed in claim 1 by the method as claimed in claim
 9. 11. Nitrogenous fertilizer as claimed in claim 10 comprising urea or urea prills coated with 0.5 to 1.0 percent by weight of the neem based composition as claimed in claim 1 by the method as claimed in claim
 9. 12. A nitrogenous fertilizer, comprising: urea; and a neem based composition that coats the urea, wherein the neem based composition includes 2-10 percent by weight neem extract based on the total weight of the neem based composition, 10-60 percent by weight neem oil based on the total weight of the neem based composition, 10-25 percent by weight binder based on the total weight of the neem based composition, and 25-50 percent by weight organic solvent based on the total weight of the neem based composition, the neem extract contains 5 to 10 percent by weight triterpenes based on the total weight of the neem based composition, the neem based composition has a density of 0.93-0.96 g/cc, an organic content of at least 70% by weight based on the total weight of the neem based composition, a total nitrogen content of 0.45-0.55% by weight based on the total weight of the neem based composition, a moisture content of 2.0% by weight or less based on the total weight of the neem based composition as measured by Karl Fischer, and a methanol solubles content of at least 20.0% by weight based on the total weight of the neem based composition, and the neem based composition is included in an amount of 0.5 to 1.0% by weight based on the total weight of the urea and the neem based composition.
 13. A nitrogenous fertilizer as claimed in claim 12, wherein the nitrogenous fertilizer comprises 5 percent by weight of the neem extract based on the total weight of the neem based layer, 40 percent by weight of the neem oil based on the total weight of the neem based layer, 15 percent by weight of the binder based on the total weight of the neem based layer and 40 percent by weight of the organic solvent based on the total weight of the neem based layer.
 14. A nitrogenous fertilizer as claimed in claim 12, wherein the triterpenes include salanin and deacetyl salanin.
 15. A nitrogenous fertilizer as claimed in claim 12, wherein the composition comprises rosin as the binder and deodorized kerosene as the organic solvent. 